Highway crossing gate



July 18, 1944- J. E. STEPHENSON HIGHWAX CROSSING GATE 2 sheets sheet 1Original Filed Dec. 20, 1938 All 99mm FIG-.2.

INVENTOR J. E. 5+ephenson B 4 HIS Afl Nl J. E. STEPHENS ON' HIGHWAYCROSSING GATE- July 18, 1944.

Original Filed. Dec. 20,- 1938 2 Sheets-Sheet 2 Ennentor (YttorncgPatented July 18, 1944 HIGHWAY CROSSING GATE James E. Stephenson,Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Original application December 20, 1938, Serial No. 246,859. Divided andthis application January 11, 1943, Serial No. 471,991

6 Claims. ('01. 188-180) This invention relates to crossing gates forvide normally energized hold-clear mechanism blocking highway traffic ona highway intersectfor electrically holding the gate in its clearposiing a railroad, and more particularly to a crosstion, whichhold-clear mechanism is released ing gate operated wholly electrically.when the clearing potential'is removed, to pro- This application is adivision of my applicavide a friction slip clutch through the medium oftion Ser. No. 246,859, filed December 20, 1938, for which the hold-clearmechanism may retard the Highway crossing gates, now Patent No.2,310,716 operation of the mechanism near the end of its granted Feb. 9,1943. clearing stroke, and to provide electro-dynamic In the electricaloperation of crossing gates braking means to retard the operation of theby reason of the length of such gates certain probi0 crossing gate inits gravitational movement from lems are encountered that have not beenenthe clearto the stop position, and to provide suitcountered in theelectrical operation of semaable centrifugal braking means for preventinphore blades for railway signallmg' purposes. too rapid operation ofthecrossing gate toward One of the obstacles surrounding the economic itsclear position. operation of crossing gates is due to the enor- Otherobjects, purposes and characteristic feamous wind resistance offered bygates of a length tures of the present invention will be pointed out toextend across a highway, by reason of which in the followingspecificationand will in part be wind resistance the operation of thegate may be obvious from the accompanying drawings, in either aided orretarded depending on the direcwhich: tion of the wind. If theelectrical operation of Fig. 1 shows in elevation a centrifugal brakethe gate is retarded this efiect may be compenwith the braking platespartly broken away; sated for by installing a higher gear ratio gearFig. 2 shows a sectional elevation of the centrain or by employing alarger motor. If, on trlfugal brake shownin Fig. 1 as viewed from leftthe other hand, the direction of the wind is such to right and along theline 2-2 of Fig. 1 ofthe as to aid the motor in moving the gate arm itis drawings; found n s y to add supplemental means for Fig.3 shows aside view of the centrifugal brake p n in excessive p e of peration f thshown in Fig. 1 with a portion thereof shown in ate arm. The secondobstacle encountered cross section taken along the line 3-3 of Fig. 1,when operating a crossing gate wholly electrically a viewed from righttoleft; and is the variable and greatly increased forces that Fi 4 howsa highway which crosses a railre enco nte ed h n the gate arm is brokenroad track and which highway is provided with as for instance y nautomobile driving electrically operated crossing gates embodying thethrough the gate. This increased force is due to present invention, themechanical and electrical the fact that the force exerted by thecounterapparatus of only one of these crossing gates beweight of thegate is in a direction to move the m shown mdetafl, V gate to its clearposition and is considerably in excess of the biasing force that existedin the 010- t Operating m posite direction before the gate was brokenoff. Referring o Fig. Of the a gs the rail. In other words, the crossinggate by reason of its road track illustrated is divided by insulatinglength is of considerable weight and in practice joints l into trackcircuits, each of which track a counterweight is added so that thebiasing force circuits energizes one of the. coils of the. interof thegate tending to move it to its stop posilocking relay R. Thisinterlocking relay R is tion is almost entirely counterbalanced. If nowpreferably of the construction shown in. either the crossing gate isbroken off, either due to exthe patent to Field No. 1,824,131 or in thepatent cessive loading as by ice or sleet, or by being to Henry et al.No. 1,969,075. This interlocking struck by an automobile, thecounterweight alone relay R through front contacts 2 and 3 includedremains, as a result of which the mechanism in series controls theslowacting repeater, relay will be operated toward its clear position at aRR. Each of the crossing gates O and P conventremendous speed. tionallyshown adjacent the highway comprises In accordance with the presentinvention it is a gate plate P, having fastened thereto a gate proposedto employ a highway crossing gate which arm l0 and a counterweight l vIn practice this is provided with a counterweight to almostneucounterweight is so located and of suchweight tralize the torqueproduced by the gate and to that the counterweight I] will greatly aidin movprovide amotor and suitable gearing for operating ing the gate 10to its clear position, but also of the gate to its clear verticalposition, and to prosuch weight that upon release of all extraneousforces the gate will gravitate to its horizontal stop position. Thisgate plate P is fastened to a main shaft I2, driven by the series motorM through the medium of gears I3, I4, I5, I6 and IT. This series motor Mincludes a series field winding F and an armatureil.v To the motor shaft29 are keyed, but freely slidable, clutch plates 2|, of which only onehas been illustrated, which clutch plates are pressed toward each otherthrough the medium of a coil spring 22 and between these clutch plates2| and freely rotatable on the shaft is a clutch wheel 23. It is. thusseen cured to the sleeve 9|. This sleeve 9| is provided with fourgrooves or keyways 93 (see Fig. 1) into which tongues on the inner plate95, the middle that this clutch wheel 23 is .frictionallyheldfrom freelyrotating on the shaft 20 by reason of the clutch plates 2| frictionallyengaging opposite sides of this clutch Wheel 23 the coil spring 22.

Under normal operating dile to actionpf 7 plate 91, and the outer plate92 project, these nection between the sleeve 9| and these plates 92, 95and 91. Two stationary braking rings or when the gate is in its clearposition and thehold- I clear mechanism HC is energized, the clutchwheel h stationary lug 33. The lower end of these plates are pivoted, asby a pin 34 passing through the vertical arm 36 of the angle lever 35-'35, this angle lever 35-36 being pivoted to stationary lugs throughthe medium of a pin31.

This toggle mechanism is normally heldin its 2 effective but in anon-toggling orn'onejlocking position by an electro-magn'et includinghigh re sistance coils H andlow resistance coils L. By a non-togglingposition ismeant a position in which upon deenergiza'tion of the magnetHC the weight of the armature'42 in addition 'tofthe force exerted onthe pawl will cause the p'awl25 to release. This electro-magnet includesthe usual back yoke 40, cores 4| and armature 142. electro-magnet whendeenergized causes the angle lever -35 to assume an abnormal position,where the stop pin 43 engages a stop plate 44, such that the lockingpawl 25 no longer engages between the lugs on the clutch wheel 23. Thiselectro-magnet is so constructed that if the high resistance coils H andthe low resistance coils'L are connected in V series and energized bythe source of direct current illustrated by the legends and there willbe insufficient flux to operate the hold-clear mechanism EC to itslocking position. If however, only-the low resistance coils L areconnected across this source of current the armature 42 will be operatedto its. at.

tracted position, thereby operating the locking pawl 25 to a position tolock the clutch wheel 23' this electro-magnet will, however, maintainitsarmature 42 in its attracted condition, if, once lifted to thisposition, by the flux'emitt'ed when the'high resistance coils H and'thelowresistanc coils .L are connected in series. across thissource ofcurrent. I

The shaft 45 illustrated by dotted lines is provided with three pairs ofcontacts46-41, 48 -49 and 50-5I. ance with the rotation of the shaft I2through the medium of gear sec'tors52and 53. In order to provideelectro-dynamic snubbingthrough the medium of the motor M when thecrossing gate I0 gravitatesto' its horizontal stop position a snubbingrelay SR, has also been provided, This This I This shaft 45 is driven inaccord- I 9 6 and 9.8 which are fastened together by a conditions, thatis,

spacer 100, a sleeve IOI, washers I02, and a rivet I03, and theseextensions 96 and 98 as riveted together are free to rotate with theshaft 20 only through an arc of about 45 degrees as permitted by thespacing of theforked ends of the bifurcated braking bracketv I05. Thislost" motion is provided to prevent any braking action taking place forat least an arc of rotation of 45 degrees following each reversal of themotor M shown in Fig. 4 irrespective of whether this motor is rotatedelectrically or is rotated by gravity through the medium of the gate orits counterweight. These stationary braking rings or washers 96 and 98are pivoted upon inwardly projecting circular extensions 92 and 95constituting parts of braking plates 92 and 95. The braking plates 92and '95 are normallyseparated by the force of compression springs I01 ofwhich only one has been illustrated. I I

To the sleeve 9| is threaded an H-shaped spider I08, Whichspider is heldin a particular threaded position by the lock screw I09 containing alock nut .I I0. This spider is so located on the sleeve 9| that thecompression springs I191 urge the inner plate 95 against the face ofthis spider I08. 'Into twoopposite ends of thisH-shaped spider I08arepivotally secured brake operating plates II2, as by trunnions I I3.These brake operating plates are'notched at their outward edges toreceive rollers II5 pivoted on pins I36. To these operating plates andto the side opposite from that engaged .by the braking plate 95 aresecured centrifugal weights I I6 as by machine screws I I 1. Thesecentrifugal weights I I6 are biased toward each other by initiallytensioned springs I I8 hooked over cotter pins II9 secured in said cen-.trifugal weights H5. The rollers II5 just barely project from the brakeoperating plates H2 in such a manner that outward movement of thecentrifugal weights I I6 will cause the brake operating plates to beturned about their trunnion I I3 so as to force the rollers I I5 againstthe inner braking plate 95, thereby causing compression of the springsI01 and movement of the braking plate 95 toward the braking 'plate 92 soas to bring all of these braking plates 95, 95, 91, 98 and 92 intofrictional engagement with each other. In this construction there havebeen provided interlocking levers I20 and I2I, of which the lever I20 isprovided with a pin I22 which engages a slot I2I contained in theinterlocking lever I 2|. These interlocking levers I20 and I2I aresecured to the weights II6 as by machine screws I24. It is thus seenthat the outward movement of one of the weights 1 I6 exerts a forcethrough the pin and slot connection between levers I20 and I'2I so that.the other weight 116 is likewise caused to move away from the shaft 20.By reason of the initial tension stored in the tension spring H8 thecentrifugal weights H6 will be maintained in their normal position, inwhich position they bear tightly against the H-shaped spider, until thespeed of the shaft 20 has exceeded a predetermined value at which timethe centrifugal weights will fly outwardly thereby causing the rollers II5 to press the plates 95 and 92 together.

This centrifugal brake functions to perform the additional result of notexerting any friction during the first 45 degrees of reversal of themotor M. This latter feature has been provided for in order to preventthe sticking together of the braking plates placing a loadupon-the motorduring electric or gravitational starting.

Referring to Fig. 4 of the drawings, let us assume that there is a trainapproaching the highway and that as a result of this train one of thecoils of the interlocking relay R is deenergized thereby opening thecircuit for the repeater relay RR and resulting in the dropping of itscontact 86. The opening of this contact 86 deenergizes the circuitincluding the high resistance coils H and the low resistance coils L ofthe hold-clear magnet in series. Deenergization of this magnet causesthe armature 42 to drop thereby causing the locking pawl 25 to be movedto the left out of engagement with theslip clutch wheel 23. By

reason of the weight of the crossing gate l0 over that of itscounterweight II, this crossing gate will gravitate toward thehorizontal position and in so doing will rotate the armature A of themotor M in the opposite direction from that in which the motor was lastelectrically operated. By reason of the residual magnetism remaining inthe motor field a voltage will be built up in the armature A which willcreate a current in the snubbing circuit in a direction to flow in thefield winding F in a direction to aid this residual magnetism, so that acomparatively strong magnetic field will b set up in the stator poles ofthe motor M. This strong magnetic field will of course set up a largercurrent through the snubbing circuit extending from the or groundconnection, through the snubbing resistance 81, through the back contact88 of the snubbing relay SR, through the armature A of the motor M,

through the field winding F of the motor M, to v the other ground orconnection, thereby ing the speed of operation of the crossing gate illtoward its horizontal stop position. If the prevailing wind should be ina direction to aid the return of the gate to an extent to cause thespeed of the gate to become too high, the centrifugal brake shown inFigs. 1-3 of the drawings will come into play and further retard thereturn of the crossing gate.

Let us now assume that the approaching train has passed the crossing andthat the repeater relay RR is again energized. Energization of therepeater relay RR causes closing of its contact 86 thereby closing acircuit through the series motor M, which may be traced from theterminal of a suitable source of direct current, front contact 86 of therelay RR, contacts 4G-4'| of the operating mechanism, low resistancewinding l of the snubbing relay SR; the armature A and the field F ofthe motor M, to the other terminal of that source of current. Thecompletion of this circuit will cause sufficient current to flow throughthe low resistance winding 1 of the snubbing relay SR to cause thissnubbing relay SR to pick up and open its back contact 88. With the backcontact 88 of relay SR opened a useful multiple path for assuringcontrol of the motor M is established which includes the high resistancewinding h of the relay SR, and the snubbing resistance 81. This multiplebranch circuit including the high resistance winding h of the relay SRassures that the contact 88 will remain open in spite of sparking at thebrushes and intermittent opening of the circuit of this motor M. As themotor operates it turns the gear sector 53 in a clockwise directionand'when it has operated through an angle of 87' degrees the contacts4849 and 50-43! are simultaneously closed. Closure of the contacts 48-49completes a circuit from the terminal through contacts 86 of relay RR,contacts 46-41 and contacts 48-49 of the operating mechanism, throughthe low resistance winding L of the hold-clear magnet, as a result ofwhich this hold-clear magnet is energized to an extent to pick up itsarmature 42. After another degreeof operation of the crossing gate in,namely, when it has been operated to the 88 degree position from itshorizontal position, the contacts 46-41 of the operating mechanism open,thereby removing the shunt which had been established around the highresistance coils H of thehold-clea'r magnet by the contacts 46-4! and48-49 in series, as a result of which the high resistance coils H andthe low resistance coils L of this hold-clear magnet are connected inseries through a circuit including front contact 86 of the relay RR andcontacts 5fl--5l of the operating mechanism'in series. This circuit byreason of the high resistance of the coils H draws very little currentbut at the same time is able to maintain the armature 42 in its raisedposition. When the armature 42 of the hold-clear mechanism was actuatedto its attracted position the locking pawl 25 of course engaged thefriction wheel 23 of the friction slip clutch as a result of which abraking action is applied to the motor M. The slipping between thefriction wheel 23 and the clutch plates 2| willsoon bring the motor M toa stop.

In order to prevent the crossing gate from being operated and heldbeyond the 91 degree position the contacts 50-5lhave been made so shortas to be closed only between the 8'7 degree and the 91 degree position.It thus follows that if the gate is operated beyond the 91 degreeposition the hold-clear magnet will be deenergized by the opening of thecontacts 50-5I. If the gate now settles back below the 91 degreeposition and the contacts 5.".-5l reclose the circuit for the holdclearmagnet its armature 42 will not be picked up, because it is incapable ofbeing picked up by a circuit including the high resistance coils H andthe low resistance coils L in series. The gate will thus be returned alittle further and when it reaches the 88 degree position and thecontacts 464! of the operating mechanism reclose, the circuitsreenergizing the motor M and for shunting the high resistance coils H ofthe hold-clear ma net are closed so that this hold-clear magnet will bepicked up through its low resistance coils L.

Let us now assume that the crossing gate is assuming its stop positionand that an automobile strikes the gate and breaks oif the arm l8 atjust about the time that the train passes beyond the crossing and picksup the repeater relay RR. When this occurs the circuit for the motor Mheretofore traced is completed 50 that the motor M is trying to operatethe gate plate P to its ;clear:position at thesametime that thecounterweight H is trying to operate the gate plate P to its clearposition. With both of these forces acting upon the shaft l2 there isa'tendency for this shaft l2 to :be rotated at a very high speed causingbreakage of the operating mechanism upon reaching the end of the stroke.Such high speed rotation of the shaft I2 is however prevented by thecentrifugal brake illustrated and shown specifically in Figs. 1-4 of thedrawings for reasons heretofore given. Also, even though the motor M isnot energized when the gate is 'brokenoff the counterweight alone mayoperate at excessive speed and bring the centrifugal brake of thecounterweight which normally counterbalances the gate itself. Although arather specific construction of applicants invention has beenillustrated 'in the drawings it is desired to be understood that thishas been done to facilitate description of the invention rather than toillustrate its scope or theparticular construction preferably employedin practicingthe invention, 'and it is further desired to be understoodthat such changes as are within the scope of the appending claims may bemade without departing .from the spirit or scope of the presentinvention.

What I claim as new is:

1. In a centrifugal brake, in combination with 'a shaft provided with aradially projecting flange, a spider secured to said shaft, a firstsetof braking plates slidably, but non-rotatably, mounted on said shaftbetween said spider and said flange,

a second set of braking plates each of which is located between twosuccessive plates of the first set, centrifugal weights provided withrollers and so pivoted to the spider that the weights, if thrown out bycentrifugal force upon rotation of said shaft, cause said rollers topress said plates together to set up frictional resistance between theplates of the first set and the plates of the second set, and means forlimiting rotation of the plates of said second set.

2. In a centrifugal brake, in combination with a'shaft provided with aradially projecting flange, a spider secured to said shaft, a first setof braking plates slidably, but non-rotatably, mounted on said shaftbetween said spider and said flange, a "second set of braking plateseach one of which is located between two successive plates of the firstset, centrifugal weights provided with rollers and so pivoted to thespider that said weights if thrown out by centrifugal force, uponrotation of said shaft, cause said rollers to press said plates togetherto set up frictional resistance between the plates of the first set andthe plates of the second set, and means allowing rotation of said secondset of plates only through a predetermining angle of rotation.

3. In a centrifugal brake, in combination with a shaft provided-with-aradially projecting flange, a spider secured to said shaft, a firstbraking plate slidably, :butznon-rotatably mounted on said shaftbetweensaid spider and said flange, a second braking plate located withits face against the first plate, centrifugal weights provided withrollers and so pivoted to the spider that said weights, if thrown out bycentrifugal force, upon rotation of said shaft, cause said rollers topress said plates together to et up frictional resistance between theplates, means allowing rotation of said second plate through only apredetermining angle of rotation, and interlocking means operativelyinterconnecting said weights to allow only substantially simultaneousand equal movements of said weights from said shaft.

4. In a centrifugal brake, in combination with a shaft provided with aradially projecting flange, a spider secured to said shaft, a firstbraking plate slidably, but non-rotatably, mounted on said shaft betweensaid spider and said flange, a second braking plate located with itsface against the first plate, centrifugal weights provided with rollersand so pivoted to the spider that said weights, if thrown out bycentrifugal force, upon rotation of said shaft. cause said rollers topress said plates together to set up frictional resistance between theplates, and means preventing rotation of said second plate.

5. In a centrifugal brake, in combination with a shaft provided with aradially projecting flange, a spider secured to said shaft, a firstbraking plate slidably, but non-rotatably, mounted on said shaft betweensaid-spider and said flange, a second braking plate located with itsface against the first plate, centrifugal weights provided with rollersand so pivoted to the spider that said weights, is thrown out bycentrifugal force, upon rotation of said shaft, cause said rollers topress said plates together to set up frictional resistance .between theplates, means preventing rotation of said second plate, and interlockmeans operatively interconnecting said weights so as to permit onlysubstantially simultaneous and equal movements thereof relative to saidshaft.

6. In crossing gate control means, in combination, a rigid rotatableshaft, a sleeve fixed to one end of the shaft and forming an outwardlyprojecting shoulder onthe shaft, a controllable friction .clutch on theshaft and including a first clutch plate slidably but non-rotatablycarried on theshaft, a second clutch plate supported on the shaft andfacing against the first clutch plate, a compression coil spring sleevedon the shaft and bearing at one end against the shoulder and the otherend against said first clutch plate, a controller effective at times tohold said second clutch plate against rotation, a centrifugal brake onsaidrigid shaft and including a radially projecting flange on the outerend of the sleeve, a spider fixed to the sleeve and inwardly spaced fromthe flange, a first braking plate slidably but non-rotatably mounted onsaid shaft between said spider and said flange, a second braking platelocated with its face against the first plate, centrifugal weightsprovided with rollers and so pivoted to the spider that said weights ifthrown out by centrifugal force upon rotation of said shaft cause saidrollers to press said plates together to set up frictional resistancebetween the plates, and means preventing rotation of said second plate.

JAMES E. STEPHENSON.

